Fan for pneumatic blowers and the like



Oct. 25, 1932. s. o. MELOS 1,884,067

FAN FOR PNEUMATIC BLOWERS AND THE LIKE Filed June 8, 1931 i I i damadd/ fi WWX W Patented Oct. 25, 1932 PATENT OFFICE SAMUEL O. MELOS, OF DES MOINES, IOWA FAN FOB PNEUMATIC BLOWERS AND THE LIKE Application filed June 8, 1931. Serial No. 542,889.

The object of my invention is to provide an improved fan designed to be rotatively mounted within a blower casing, and when 50 mounted will provide eflicient means for delivering comparatively heavy material from a position within said casing outwardly through a vertically arranged discharge pipe, such as used in pneumatic conveyors, and so constructed that a maximum amount of material may be delivered with a min imum amount of air.

A further object is to provide a fan for blower casings which may be cast ina single piece of metal, and so shaped that the fan will operate comparatively close to the walls of the casing, in which it is mounted, and.

at the same time permit a comparatively large amount of material to be easily delivered to the same without clogging, through a comparatively small feed opening. My invention consistsin the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter more fullyset forth, pointed out inmy claims, and illustrated in the accompanying drawing, in which: I

Figure 1 illustrates the front edge of my improved fan blade.

Figure 2 is a side elevation of the same.

Figure 3 shows the manner in which the fan is mounted in a blower casing, said casing having one of its side members removed. Figure 4 1s a detail sectional vlew taken on the hue H of Flgure 3.

Figure 5 illustrates the back edge of the fan blade. v

Figure 6 illustrates one end of the fan blade.

- Figure 7 is'a detail sectional view taken on the line 7-7 of Figure 2.

Figure 8 is a detail sectional view taken on the line 8-8 of Figure 2.

Figure 9 is a detail sectional view taken on the line 99 of Figure 2. l

My improved fan blade comprises a hub 10 having an opening 11 for receiving a drive shaft, said opening having a key seat 12.

The hub 10 is provided with laterally projecting blade members 13. The working face 14. of each blade is preferably supported tangentially with the hub portion 10. Said working faces connect the hub at diametrically opposite points.

The back edge 15 of each blade tapers inwardly and outwardly from the hub portion in the manner clearly illustrated in Figure 5, with one of its edges in alinement with the adjacent working face. The front edge 16 of each of the blades is comparatively thin and of substantially'uniform thickness and parallel with the working face.

' The back face of each blade connects the backedges of the face members 15 and 16, assuming a warped and somewhat helical sur-' face. This construction leaves the back edges of the blades wider than the front edges, as shown in Figures 8 and 9.

The inner ends of the front edges 16 are curved'inwardly to form recesses 17, and

thus provide means whereby the material may be more easily fed into the fan casing The inner ends of the back edges 15 are also provided with recesses 18 which lighten the construction. Theentire fan blade is formed of a single piece of cast metal.

Each of the blades has openings 19 and 20, the openings 19 being near the outer ends of the blades, and one near the front edge and the other near the back edge. The openings 20 are intermediate theopenings 19 with one of the openings near the front edge and the other opening near the back edge. The open ings of one blade are in staggered relation with those of the. other blade, in such manner that as the blade is rotated any particles of material passing through one of the openings would not also pass through the next following opening.

Said openings 20 permit a certain amount of air to pass backwardly through the openings to decrease the amount of vacuum back of the blade, and to decrease the amount of air discharged through the outlet opening 21 '05 of the fan casing 22. The front end of the casing 22 is provided with an inlet opening 23, while the blade is supported on a suit.ble shaft 24, one end of which projects into the casing. The fan is designed to rotate in a 109 counterclockwise direction, as illustrated in openin 23, causing the material to enter the casing ack of the blades 14,; where it will be delivered outwardly toward the outer ends of the blades by centrifugal force, and delivered upwardly through the discharge opening 21.

I have found by actual'practice that a considerable advantage is gained by placing the openings 19 and 20 in the fan blades, and that a considerable amount of power is saved, due to the fact that considerably less air delivered through. the discharge opening 21 which is usually connected with a long dis.- charge: pipe. The. ground feed is delivered to a chamber where it is separated from'the air.

By cutting down the amount of air delivered through the discharge pipe, the necessity of a large air separator is eliminated. This is of particular advantage when the blower is used in connection with the small portable mills which are now in extensive i to be delivered over the end of the fan blade is increased, thereby decreasing the loss of power due to the friction. of the material passing outwardly over the front face of the blade, and .thereby resulting in consider- 7 able savingin power. 7

By forming the front edge of the blades comparatively thin and providing the cut away portions 17 it will be seen that a comparatively small amount of blade area is adjacent to the inlet opening 23, and thus providing a space of comparatively largearea through which the material may easily enter mission means between the power device and "the fan shaft.

Thus it will be seen that I have provided a fan blade of comparatively simple. construction, which may be cast of a single piece of metal, in which the actual manufacturing cost isreduced. to a minimum, and at the same time I' have provided a fan blade in which the amount of power for its'operation is reduced and in which the volume of air delivered by the fan is also reduced, and which is highly efficient when used in pneumatic blowers for the purpose of delivering the material to suitable conveyors.

I claim as my invention:

1. The combination of a cylindrical 038- ing having central opening at one end and a. tangentially arranged discharge opening in its periphery, ashaft extending into said casing, a. fan blade on thecinner'end of the said shaft, said blade comprising a hub having oppositely projecting blades, the front face of each blade being tangent to said hub, the back'edge. of each blade tapering inward; ly toward its outer end, the front edge of each blade being comparatively thin and parallel with said face, the central portion of each of said blades having openings connecting its front and back faces. I

2.'A fan comprising'a hub having oppositely'projecting blades, the front face of each blade being tangent to said hub, the back edge of each blade tapering inwardly toward its outer end, the front edge of each blade being comparatively thin and parallel with said face, each of said blades having openings connecting its front and back faces, the openings of one blade'being in staggered relation with those of the other blade.-

3.. The combination of a fan casing having inlet and outlet openings, a shaft having one 1 end projecting into said casing, a fan carried by the inner end of said shaftfcomprising a. hub portion, a laterally projecting blade, and an opening in the central portion of said'blade connecting its front and back T20 faces. 7

4.7A fan comprising a hub having laterally and oppositely projecting blades, the front face of each blade being tangent to said hub, the frontedge of each blade being comparatively thin and the back edge comparatively thick, each blade having an 0pening connecting its front and back faces.

5. Afan comprising a hub having laterally and oppositely projecting blades, the front face of each blade being tangent to said hub, the front edges of the back and front faces being parallel, the back edges of the back and front faces being substantially tangent to opposite sides of said hub and converging near their outer ends.

Des Moines, Iowa, June 5, 1931.

SAMUEL O. MELOS. 

